Add compatibility with lxc 3

etc/lxc.3.config.in

@@ -0,0 +1,38 @@
+lxc.tty.max = 4
+lxc.pty.max = 1024
+lxc.rootfs.path = ROOTFS
+lxc.arch = ARCH
+lxc.cgroup.devices.deny = a
+# /dev/null and zero
+lxc.cgroup.devices.allow = c 1:3 rwm
+lxc.cgroup.devices.allow = c 1:5 rwm
+# consoles
+lxc.cgroup.devices.allow = c 5:1 rwm
+lxc.cgroup.devices.allow = c 5:0 rwm
+lxc.cgroup.devices.allow = c 4:0 rwm
+lxc.cgroup.devices.allow = c 4:1 rwm
+# /dev/{,u}random
+lxc.cgroup.devices.allow = c 1:9 rwm
+lxc.cgroup.devices.allow = c 1:8 rwm
+lxc.cgroup.devices.allow = c 136:* rwm
+lxc.cgroup.devices.allow = c 5:2 rwm
+# rtc
+lxc.cgroup.devices.allow = c 254:0 rwm
+
+# mounts points
+lxc.mount.entry=proc ROOTFS/proc proc nodev,noexec,nosuid 0 0
+lxc.mount.entry=sysfs ROOTFS/sys sysfs defaults  0 0
+
+# Container with network virtualized using a pre-configured bridge named br0 and
+# veth pair virtual network devices
+# On the host, run: ifconfig br0 up 10.0.2.2
+# Alternatively, you can use another IP range for the bridge interface, in this case set
+# the environment variables GITIAN_HOST_IP and LXC_GUEST_IP appropriately.
+lxc.net.0.type = veth
+lxc.net.0.flags = up
+lxc.net.0.link = GUESTLINK
+lxc.net.0.ipv4.address = GUESTIP/24
+lxc.net.0.ipv4.gateway = auto
+
+lxc.uts.name = gitian
+

libexec/config-lxc

@@ -10,4 +10,15 @@ if [ -z "$LXC_BRIDGE" ]; then
     LXC_BRIDGE=br0
 fi
 
-sed "s;ROOTFS;$wd/target-$LXC_SUITE-$LXC_ARCH;;s;ARCH;$LXC_ARCH;g;;s;GUESTIP;$LXC_GUEST_IP;g;s;GUESTLINK;$LXC_BRIDGE;g" < etc/lxc.config.in > var/lxc.config
+OLD_IFS=$IFS
+IFS=.
+VERSION=($(lxc-start --version))
+IFS=$OLD_IFS
+
+if [ $VERSION -ge 3 ]; then
+    LXC_CONFIG=etc/lxc.3.config.in
+else
+    LXC_CONFIG=etc/lxc.config.in
+fi
+
+sed "s;ROOTFS;$wd/target-$LXC_SUITE-$LXC_ARCH;;s;ARCH;$LXC_ARCH;g;;s;GUESTIP;$LXC_GUEST_IP;g;s;GUESTLINK;$LXC_BRIDGE;g" < $LXC_CONFIG > var/lxc.config